c#-5.0

Error CS1056: Unexpected character ‘$’ running the msbuild on a tfs continuous integration process

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The problem can be fixed installing a Nuget package Microsoft.Net.Compilers. Below is the link of my highlighted answer: Project builds fine with Visual Studio but fails from the command line That feature is a syntactic sugar for C#6, try to install the latest version of the framework 4.6.2 https://www.microsoft.com/en-us/download/details.aspx?id=53345 Then go to your Project properties … Read more

Request.Content.ReadAsMultipartAsync never returns

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I ran into something similar in .NET 4.0 (no async/await). Using the debugger’s Thread stack I could tell that ReadAsMultipartAsync was launching the task onto the same thread, so it would deadlock. I did something like this: IEnumerable<HttpContent> parts = null; Task.Factory .StartNew(() => parts = Request.Content.ReadAsMultipartAsync().Result.Contents, CancellationToken.None, TaskCreationOptions.LongRunning, // guarantees separate thread TaskScheduler.Default) .Wait(); … Read more

Why doesn’t generic ICollection implement IReadOnlyCollection in .NET 4.5?

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There are probably several reasons. Here are some: Huge backwards compatibility problems How would you write the definition of ICollection<T>? This looks natural: interface ICollection<T> : IReadOnlyCollection<T> { int Count { get; } } But it has a problem, because IReadOnlyCollection<T> also declares a Count property (the compiler will issue a warning here). Apart from … Read more

How do you create an asynchronous method in C#?

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I don’t recommend StartNew unless you need that level of complexity. If your async method is dependent on other async methods, the easiest approach is to use the async keyword: private static async Task<DateTime> CountToAsync(int num = 10) { for (int i = 0; i < num; i++) { await Task.Delay(TimeSpan.FromSeconds(1)); } return DateTime.Now; } … Read more

Using async without await?

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You still are misunderstanding async. The async keyword does not mean “run on another thread”. To push some code onto another thread, you need to do it explicitly, e.g., Task.Run: await Task.Run(() => Logger.LogInfo(“Pushing new call {0} with {1} id”.Fill(callNotificationInfo.CallerId)); I have an async/await intro post that you may find helpful.

How to implement INotifyPropertyChanged in C# 6.0?

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After incorporating the various changes, the code will look like this. I’ve highlighted with comments the parts that changed and how each one helps public class Data : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; protected void OnPropertyChanged([CallerMemberName] string propertyName = null) { //C# 6 null-safe operator. No need to check for event listeners //If there … Read more

Task.Yield – real usages?

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When you see: await Task.Yield(); you can think about it this way: await Task.Factory.StartNew( () => {}, CancellationToken.None, TaskCreationOptions.None, SynchronizationContext.Current != null? TaskScheduler.FromCurrentSynchronizationContext(): TaskScheduler.Current); All this does is makes sure the continuation will happen asynchronously in the future. By asynchronously I mean that the execution control will return to the caller of the async method, … Read more

Is async/await suitable for methods that are both IO and CPU bound?

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There are two good answers already, but to add my 0.02… If you’re talking about consuming asynchronous operations, async/await works excellently for both I/O-bound and CPU-bound. I think the MSDN docs do have a slight slant towards producing asynchronous operations, in which case you do want to use TaskCompletionSource (or similar) for I/O-bound and Task.Run … Read more

Do the new C# 5.0 ‘async’ and ‘await’ keywords use multiple cores?

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Two new keywords added to the C# 5.0 language are async and await, both of which work hand in hand to run a C# method asynchronously without blocking the calling thread. That gets across the purpose of the feature, but it gives too much “credit” to the async/await feature. Let me be very, very clear … Read more

Await in catch block

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Update: C# 6.0 supports await in catch Old Answer: You can rewrite that code to move the await from the catch block using a flag: WebClient wc = new WebClient(); string result = null; bool downloadSucceeded; try { result = await wc.DownloadStringTaskAsync( new Uri( “http://badurl” ) ); downloadSucceeded = true; } catch { downloadSucceeded = … Read more